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You seem to have thought all this through pretty well. Given your budget and intentions, your choice of suitable boats is going to be a bit limited.
While the shoal draft capability of the Oday may seem attractive, in reality in our waters it's rarely needed. The other side of a centerboarder is that it's likely trailerable. In Vancouver, with its moorage shortage, this will be a larger advantage.
Will the O'Day be OK for our waters? Possibly, but to be honest you see few boats that small (esp swing keels) cruising/crossing the Strait. While the weather forecasting is quite good for the most part, they don't always get it right and I'd be a bit concerned being halfway across Georgia Strait and have an unexpected serious breeze pop up. The stability of a slightly larger fixed keel boat would be nice to have in those conditions.
If you planned to trailer the boat to the islands, or to Desolation, then it gets to be a more viable proposition, but you're into some hefty ferry fares for a vehicle and a trailer - being a bit cash strapped that'll be a problem.
As you noted, O'Days are not exactly common around here and will be difficult to find. For similar money you might find a decent Shark 24, or a Thunderbird. Either of these will make much better BC cruisers (IMO) than any centerboarder. But - then you have to find a place to moor it. You will have better luck in that size range than over 30 feet, but it won't be cheap.
Another good candidate not so rare here is a Tanzer 22, they are available both swing and fixed keel. The Cal 22 in the link below looks like a nice boat too. These three came up in a YW search for boats in the PNW between $4-6K and 20 - 25 feet.
btw - it's very common nowadays for Vancouver buyers to bring boats up from the NW United States (mostly because of the much larger selection). Importing is not complicated.
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